NIAMS ARRA Chronicles

Photo ID: Maureen Devlin, Ph.D. (second from left) and Mary Bouxsein, Ph.D. (second from right) along with two research assistants.

With the help of funds from the American Recovery and Reinvestment Act (ARRA), researchers at Beth Israel Deaconess Medical Center in Boston have found a connection between calorie restriction in perinatal mice and impaired bone health. The discovery, made by Mary Bouxsein, Ph.D., Maureen Devlin, Ph.D., and their team, results from their ARRA grant to explore how maternal diet and the perinatal environment influence the course of skeletal growth and development. The grant is administered through the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

Although scientists have known that restricting calories results in lower bone mass in adult rodents, much less is known about how caloric limitation affects young animals in a rapid growth phase. Using 3-week-old weaned mice, the investigators created a group to be fed a diet with a 30 percent caloric restriction and another group to receive a normal diet. At 6 and 12 weeks of age, they checked the animals for such bone health indicators as bone mass, density, length and architecture; levels of leptin, a hormone involved in appetite and metabolism; and levels of insulin-like growth factor 1 (IGF-1), a hormone important in childhood growth. Compared with the control group, the calorie-restricted mice were smaller, with lower bone mineral density. The experimental mice also had 52 and 88 percent lower serum leptin levels and 33 and 39 percent lower serum IGF-1 levels at 6 and 12 weeks. Additionally, the researchers saw an increase in bone marrow fat in the experimental animals, a condition seen in girls with anorexia nervosa, who also have poor skeletal health.

“These results support the hypothesis that caloric restriction during rapid skeletal growth is harmful to bone mass and architecture,” says Dr. Bouxsein. “Our continuing work on how perinatal and maternal diets influence bone mass acquisition might help to establish diet as a modifiable risk factor for adult bone disease,” notes Dr. Devlin.

According to the investigators, ARRA funding has been essential to the project’s success. The grant has allowed them to retain a key postdoctoral fellow and to hire three new previously unemployed research assistants to move the work forward. And, for at least one of the research assistants, her new position has been a welcome “jump start” for her scientific career.

“Poor bone health is a significant issue for our aging population,” says Dr. Bouxsein. “ARRA is helping us to pursue its root causes.”